1. Field of the Invention
The present invention is directed generally to the hyperthermic treatment of cancer, and, more particularly, to a system and method for hyperthermic treatment using permanent magnets.
2. Description of the Related Art
The human body uses heat to fight disease, naturally. This phenomenon is called fever. The higher temperature increases metabolic activity and allows the body to fight the disease more effectively.
In a similar fashion, researchers are using heat to attack cancer cells. According to the National Cancer Institute, hyperthermia cancer treatment kills cancerous cells by elevating their temperatures to a therapeutic range of 108°-113° Fahrenheit (° F.). Hyperthermia is a well known thermal therapy wherein the cytotoxic effects of elevated temperatures in tissue are induced to achieve cell death or render the cells more vulnerable to ionizing radiation or chemical toxins.
Many new technologies are being developed to address the need to cure diseases in humans and animals, especially in the field of Oncology. Treatments ranging from Hyperthermia to Radiation are being offered either individually or in conjunction with each other to combat the disease at its source, the tumor and cancerous cells. Efforts to develop ways to target localized heat to affected areas of the body and skin range from Radio Frequency (RF) ablation, Microwave Hyperthermia, X-ray and Magnetite Hysteresis.
These prior art technologies all use different types of electromagnetic waves. The higher the energy of the particles of electromagnetic waves the shorter the wavelength, with x-rays being the shortest and radio waves the longest. Electromagnetic waves travel through any material as well as through a vacuum. When electromagnetic waves hit an object, they slow down as their energy decreases and the wavelength becomes longer, generating heat at the surface of the object that in turn causes the particles of that object to vibrate.
The heat and vibration of the particles depends on the wavelength and energy of the electromagnetic wave and relates directly to the heat sources for the above mentioned treatments. Electromagnetic (radio frequency and microwave) devices are adjusted by controlling their power supply and frequencies. These parameters must be recalculated for each treatment session to reduce the margin of errors.
The downsides of these prior art technologies can be numerous. With RF ablation if the temperature is too high, vaporization and charring limit the effective volume of tissue that may be treated. Nearby blood vessels may also affect treatment by acting as a heat sink to cool the diseased site, or by diverting energy away from the target acting as energy sink because blood is more thermally conductive than other tissues. Microwave hyperthermia energy applied externally can cause surface burns and blisters and damage tissues between the treatment site and the body's surface. Metallic implants within the patient may also become excessively heated by the microwaves. Magnetite Hysteresis is hampered by a lack of cellular selectivity and by characteristically uneven distribution. Further downsides include the limited ability to treat the diseased area from distances greater than 0.1″ (inches) deep due to the expanding exposure of unwanted energy in the surrounding soft tissues and blood.
The common difficulty with RF and microwave heat treatments seems to center in delivering repeatable, controllable heat to the desired diseased site without causing negative effects to the surrounding surface and soft tissues. This task is made more difficult by the varying density and water content of various tissues ranging from blood to bone and the preferential heat absorption and electrical conductivity of each type of tissue. There is also significant complication with delivering the required heat deep within the body as the microwave energy is significantly disbursed before it gets to the target. Unfortunately healthy tissues also absorb microwave, laser, and ultrasound energy. These factors are significant because each treatment site for each patient requires careful calculation of its own set of parameters for safety and effectiveness.
Therefore, it can be appreciated that there is a significant need for techniques for hyperthermic treatment that reduces side effects and non-desirable heating and may be controlled in a predictable, repeatable fashion. The present invention provides this, and other advantages, as will be apparent from the following detailed description and accompanying figures.